After months of threatening to wage a nuclear war,North Korea did an about-face Sunday and issued a surprise proposal to the United States,its No. 1 enemy: Let’s talk.

But the invitation from North Korea’s National Defense Commission,the powerful governing body led by leader Kim Jong Un,comes with caveats: No preconditions and no demands that Pyongyang give up its prized nuclear assets unless Washington is willing to do the same  ground rules that make it hard for the Americans to accept.

Washington responded by saying that it is open to talks  but only if North Korea shows it will comply with U.N. Security Council resolutions and live up to its international obligations.

“As we have made clear,our desire is to have credible negotiations with the North Koreans,but those talks must involve North Korea living up to its obligations to the world,including compliance with U.N. Security Council resolutions,and ultimately result in denuclearization,” U.S. National Security Council spokeswoman Caitlin Hayden said in a statement. “We will judge North Korea by its actions,and not its words and look forward to seeing steps that show North Korea is ready to abide by its commitments and obligations.”

North Korea’s call for “senior-level” talks between the Korean War foes signals a shift in policy in Pyongyang after months of acrimony.

Pyongyang ramped up the anti-American rhetoric early this year after its launch of a long-range rocket in December and a nuclear test in February drew tightened U.N. and U.S. sanctions. Posters went up across the North Korean capital calling on citizens to “wipe away the American imperialist aggressors,” slogans that hadn’t been seen on city streets in years.

The U.S. and ally South Korea countered the provocations and threats by stepping up annual springtime military exercises,which prompted North Korea to warn of a “nuclear war” on the Korean Peninsula.

But as tensions began subsiding in May and June,Pyongyang began making tentative,if unsuccessful,overtures to re-establish dialogue with Seoul and Washington.

Earlier this month,it proposed high-level talks with South Korea  the first in six years. But plans for two days of meetings last week in Seoul dramatically fell apart even before they began amid bickering over who would lead the two delegations.

Meanwhile,the virulent anti-American billboards plastered across the city were taken down. And on Sunday,as scores of people fanned out across Pyongyang to help carry out the latest urban renewal projects in the capital  landscaping and construction  the National Defense Commission issued a statement through state media proposing talks with the U.S. to ease tensions and discuss a peace treaty formally ending the Korean War.

One army officer,a director at the top military academy for North Korean youths,said he read about the proposal for talks in the newspaper.

“If they have talks and they go well,that’s good,” Jang Chun Hyon said Monday at the Mangyongdae Revolutionary School. “But we in the army will firmly hold onto our rifles and be ready to fight whether the talks are going smoothly or not.”

“Denuclearization can only be realized if the U.S. can guarantee that the whole peninsula is denuclearized,” he said,repeating what he read in the paper. “The hostile U.S. should forget their anti-republic policies.”

North Korea fought against U.S.-led United Nations and South Korean troops during the three-year Korean War in the early 1950s,and Pyongyang does not have diplomatic relations with either government. The Korean Peninsula remains divided by a heavily fortified border.

Reunifying the peninsula was a major goal of North Korea’s two late leaders,Kim Il Sung and Kim Jong Il,and is a legacy inherited by current leader Kim Jong Un. North Korea is expected to draw attention to Korea’s division in the weeks leading up to the 60th anniversary in July marking the close of the Korean conflict,which ended in an armistice. A peace treaty has never been signed formally ending the war.

Across Pyongyang,signboards at construction sites are marked with a countdown to July 27,giving laborers a deadline for retiling the roof of the People’s Palace of Culture,renovating the Korean War museum,and planting trees and grass meant to beautify the city for the milestone anniversary.

For the nation’s leaders,July 27 may well be their deadline for drawing the United States to the negotiating table to discuss a peace treaty.

But for Washington,there will be no talks just for talks’ sake,officials say.

Speaking on CBS television’s “Face the Nation” show Sunday,President Barack Obama’s chief of staff,Denis McDonough,said Washington has been “quite clear” that officials support dialogue and have engaged Pyongyang in talks in the past.

But “those talks have to be real. They have to be based on them living up to their obligations,to include on proliferation,on nuclear weapons,on smuggling and other things,” he said. “And so we’ll judge them by their actions,not by the nice words that we heard yesterday.”

He said smooth talk will not help Pyongyang evade U.N. sanctions supported by Moscow and Beijing,North Korea’s two traditional allies. U.N. Security Council resolutions ban North Korea from developing its nuclear and ballistic missile programs.

Earlier this year,Kim Jong Un enshrined the drive to build a nuclear arsenal,as well as expand the economy,in North Korea’s constitution. Pyongyang,estimated to have a handful of crude nuclear devices,says it needs to build atomic weapons to defend itself against what it sees as a U.S. nuclear threat in Korea and the region.

The National Defense Commission reiterated its refusal to give up its nuclear ambitions until the entire Korean Peninsula is free of nuclear weapons,a spokesman said in a statement carried by the Korean Central News Agency.

“The denuclearization of the Korean Peninsula does not only mean ‘dismantling the nuclear weapons of the North'” but also should involve “denuclearizing the whole peninsula,including South Korea,and aims at totally ending the U.S. nuclear threats” to North Korea,the spokesman said.

The U.S. denies having nuclear bombs in South Korea,saying they were removed in 1991. However,the U.S. military keeps nuclear submarines in the region and has deployed them for military exercises with South Korea.

After blaming Washington for raising tensions by imposing “gangster-like sanctions” on North Korea,the spokesman called on the U.S. to propose a venue and date for talks  but warned against setting preconditions.

Washington has been burned in the past by efforts to reach out to Pyongyang.

Months of behind-the-scenes negotiations yielded a significant food-for-disarmament deal in February 2012,but that was scuttled by a failed North Korean long-range rocket launch just weeks later.